Metal cleaning technology has remained relatively unchanged for many years. Recent improvements in the cleaning technology include additional cleaning tanks, increased pressure and higher operating temperatures. The majority of the improvements have been mechanical in nature as opposed to chemical.
Environmental concerns have led the industry to seek metal cleaning methods which produce less waste. Traditional cleaning and degreasing methods produce alkaline waste which poses an environmental hazard. The volume of the alkaline waste is great enough to warrant concern, since millions of dollars have to be spent each year in disposing of the waste. Waste in massive quantities is inherent in the way the cleaning chemicals are conventionally sold.
Metal cleaning chemicals are conventionally sold in one package to be added to water to provide a cleaning solution that removes protective oils, carbonaceous matter, alkaline salts and other residues from metal surfaces. The one package metal cleaner is pre-blended in the required ratio to provide best results for the particular cleaning to be performed. Two basic problems result.
First, the chemical components which are consumed at a faster rate than the others determine the lifetime of the cleaning solution. This increases waste because a portion of the solution in the tank must be drained before fresh chemicals are added. Such waste is an environmental hazard and disposing of it is a costly procedure. It has been shown that when the soil concentration raises above 1%, the cleaning ability of the cleaning solution deteriorates dramatically.
Second, it is difficult to optimize metal cleaning operations for specific residue encountered on individual metal surfaces from different suppliers. The problem arises because the ratio of chemical components in conventional cleaners is fixed and cannot be changed when cleaning metals from different suppliers. One cleaning composition simply cannot work efficiently for all metal cleaning as the coatings are different from one supplier to the next.